Vulcanization accelerators



United States Patent 3,379,700 VULCANIZATION ACCELERATORS John J.DAmico, Dunbar, W. Va., assignor to Monsanto Company, St. Louis, Mo., acorporation of Delaware N0 Drawing. Filed Dec. 13, 1965, Ser. No.513,558 6 Claims. (Cl. 260-795) This invention relates to derivatives ofphthalazine and 1H-1,2,4-triazole. The invention further relates to newchemical compounds useful as vulcanization accelerators in rubber.

An object of this invention is to provide new and useful chemicalcompounds for industry. A further object of this invention is to promotethe progress of science and useful arts. Other objects will becomeapparent as the description proceeds.

The new compounds of the invention may be represented by the formulawherein R and R are lower alkyl, lower cycloalkyl, aryl preferably ofthe benzene series, or R and R taken together are an open chain radicalwhich with the nitrogen constitute a heterocyclic ring which preferablycontains at least five members, at least four of which are carbon andnot more than one is nitrogen. T may be wherein A is orthophenyleneeither unsubstituted or substituted by One or more halogen, lower alkyl,or lower alkoxy substituents and Z is oxygen, sulfur, or NH. And T maybe carbamoyl, carbanilino, carboxy, or hydrogen and R' is lower alkyl.For example, where the radical is lH-l,2,4-triazol--yl orphthalazin-l-yl, T may be N- alkyl-N-aryl thiocarbamoyl,N,N-(oxapentamethylenethiocarbamoyl, N,N-diloweralkyl thiocarbamoyl,4,6-dimethylpyrimidin-Z-yl, 4-methyl-thiazol-2-yl, (4-methyl-5-acetyl)thiazol 2 yl, (4-methy'l-5-carbamoyl)thiazol-Z-yl, (4 methyl 5carbanilino)thiazol-Z-yl, (4-methyl-5-carboxy)thiazol-2-yl,N,N-hexamethylene thiocarbamoyl, or an unsubstituted 2-benzothiazolyl,2-benzoxazolyl or 2- benzimidazolyl radical or a substituted2-benzothiazolyl, 2-benzoxazolyl or Z-benzimidazolyl radical substitutedin the 5 or 6 position with a halogen or lower alkoxy radical.

"'ice In this invention, the term lower includes 1 to 8 carbon atoms.

Suitable examples of the compounds of this invention are:

1-( Z-benzothiazolylthio phthalazine,

S- (phthalazinl-yl N,N-3-oxapentamethylenedithiocarbamate,

S-(phthalazin-1-yl)N,N-diethyldithiocarbamate,

1- 6-ethoxy-Z-benzothiazolylthio phthalazine,

1- S-chloro-2-benzothiazolylthio phthalazine,

1- 2-benzoxazolylthio phthalazine,

l- Z-benzimidazolylthio phthalazine,

l- (4-methyl-S-acetyI-Z-thiazolylthio phthalazine,

S- phthalazin-l-yl N,N-tetramethylenedithiocarbamate,

S- phthalazinl-yl N,N-pentamethylenedithiocarb amate,

S- (phthalazinl-yl) N,N-hexamethylenedithiocarbamate,

8- (phthalazinl-yl N,N-dimethyldithiocarbamate,

S- phthalazinl-yl N,N-diisopropyldithiocarbamate,

l-[ (4-methyl-5-carbamoyl -2-thiazolylthio] phthalazine,

1- 4-methyl-2-thiazolylthio phthalazine,

1-[ 4-methyl-5-carbanilino -2-thiazolylthio] phthalazine,

1-[ 4-methyl-5-carboxy -2-thiazolylthio] phthalazine,

1- (4,6-dimethyl-2-pyrimidinylthio phthalazine,

S-( lH1,2,4-triazol-5-yl) N,N-dipropyldithiocarbamate,

S- 1H-1,2,4-triazol-5-yl) N-ethyl-N-cyclohexyldithiocarb amate,

S- 1H-1,2,4-triazol-5-yl N,N-dibutyldithiocarbamate,

S-( lH-l ,2,4-triazol-5-yl) N,N-diethyldithiocarbamate,

S-( 1H-1,2,4-triazol-5-yl)N-ethyldithiocarbanilate 5-2-benzothiazolylthio) lH- 1,2,4-triazole,

S-( ll-l- 1 ,2,4-triazol-5-yl N,N-B-oxapentamethylenedithiocarbamate,

5- 6-ethoxy-2-benzothiazolylthio) lH-1,2,4-triazole,

5- S-chloro-2-benzothiazolylthio) 1H-1,2,4-triazole,

5- 2-benzoxazolylthio) lH- 1,2,4-triazole,

5- Z-benzimidazolylthio) 1H-1,2,4-triazole,

5- (4-met11yl-S-acetyl-Z-thiazolylthio) lH-l ,2,4-triazole,

S-( 1H-1,2,4-triazol-5-yl)N,N-tetramethylenedithiocarbamate,

S 1H 1 ,2,4-triazol-5-yl N,N-pentamethylenedithiocarb amate,

S-( 1H- 1,2,4-triazol-5-yl N,N-hexamethylenedithiocarbamate,

S-( 1H-1,2,4-triazol-5-yl N,N-dimethyldithiocarbamate,

S-( 1H-1,2,4-triazol-5-yl)N,N-diisopropyldithiocarbamate,

5- (4-methyl-5-carbarnoyl) -2-thiazolylthio] 1H-1,2,4-

triazole,

5- 4methyl-2-thiazolylthio) lH1,2,4-triazole,

S-[ 4-methyl-5-carbanilino -2-thiazolylthio] 1H-1,2,4-

triazole,

5- 4-methyl-5-carboxy) -2-thiazolylthio] 1H-1,2,4-

triazole,

5- 4,6-dimethyl-2-pyrimidinylthio) lH- 1,2,4-triazole,

S- (phthalazin-l-yl N,N-dipropyldithiocarbamate,

S- (phthalazinl-yl -N-methyl N-cyclohexyldithiocarb amate,

S-(phthalazin-l-yl)N,N-dibutyldithiocarbarnate, and

S- (phthalazin-l-yl N,ethyldithiocarbanilate.

The new compounds of this invention are prepared as follows:

The compound 1-(2-benzothiazo1ylthio)phthalazine is prepared by addingin one portion 16.5 grams (0.1 mole) of l-chloro phthalazine to astirred solution containing 17.2 grams (0.1 mole) of 97%2-mercaptobenzothiazole, 300 ml. of ethyl alcohol, and 6.3 grams (0.1mole) of 90% potassium hydroxide. The stirred reaction mixture is heatedat 80 C. for 24 hours. The mixture is cooled to 25 C. and 500 ml. ofwater is added. Stirring is continued for 15 minutes at 25-30 C. Theresulting solid is collected by filtration, washed with water untilneutral to litmus and air dried at 25-30 C. The product, melting point166168 C., is obtained in an 88% yield. After recrystallization fromethyl alcohol, a sample of the product melts at 172173 C. Analysis ofthe l-(2-benzothiazolylthio)phthalazine shows 14.12% nitrogen and 21.62%sulfur. Calculated percentages for C H N S are 14.23% nitrogen and21.70% sulfur. The infrared spectrum confirms the structure of1-(2-benzothiazolylthio) phthalazine.

The compound 1-(6-ethoxy 2 benzothiazolythio)- phthalazine is preparedin a similar manner as described above except 21.2 grams (0.1 mole)6-ethoxy-2-mercaptobenzothiazole is used as a reactant in place ofZ-mercaptobenzothiazole and the reaction is stirred at reflux for fivehours. The product, melting point 130-135 C., is obtained in a 62.4%yield. After recrystallization from an ethyl alcohol acetone mixture, asample of the product melts at 141143 C. Analysis of the 1-(6 ethoxy-2-benzothiazolylthio)pahthalazine shows 12.62% nitrogen and 18.83% sulfur.Calculated percentages for C1'1H13N3 are 12.39% nitrogen and 18.87%sulfur.

The compound 1-(5-chloro 2 benzothiazolythio)- phthalazine is preparedin a similar manner as described above except 20.2 grams (0.1 mole) of5-chloro-2-mercaptobenzothiazole is used as a reactant in place of 2-mercaptobenzothiazole. The product, melting point 199 201 C., isobtained in a 70% yield. After recrystallization from benzene, a sampleof the product melts at 204- 205 C. Analysis of the1-(S-chloro-2-benzothiazolylthio)phthalazine shows 12.59% nitrogen,19.12% sulfur and 10.60% chlorine. Calculated percentages for C H ClN Sare 12.74% nitrogen, 19.44% sulfur, and 10.75% chlorine.

The compound 1- (4-methyl-5-carbamoyl) -2-thiazolylthio]phthalazine isprepared in a similar manner as described above except 17.4 grams (0.1mole) of 2-mercapto-4-methyl-5-carbamoyl thiazole is used as a reactantin place of 2-mercaptobenzothiazole. The product, melting point 228229C., is obtained in a 73% yield. Analysis of the1-[(4-methyl-5-carbamoyl)-2-thiazolylthio]phthalazine shows 18.28%nitrogen and 20.74% sulfur. Calculated percentages for C H N OS are18.53% nitrogen and 21.21% sulfur.

The compound 1-(4-methyl-2-thiazolylthio)phthalazine is prepared in asimilar manner as described above except 13.2 grams (0.1 mole)2-mercapto-4-methylthiazole is used as a reactant in place ofZ-rnercaptobenzothiazole. The product, melting point 117-120 C., isobtained in a 69.5% yield. After recrystallization from ethyl alcohol, asample of the product melts at 124-125 C. Analysis of the1-(4-methyl-2-thiazolylthio)phthalazine shows 15.85% nitrogen and 24.17%sulfur. Calculated percentages for C H N S are 16.20% nitrogen and24.73% sulfur.

The compound 1- (4-methy1-5-carbanilino) -2-thiazolylthio]phthalazine isprepared by adding in one portion 10 grams (0.0605 mole) of l-chlorophthalazine to a stirred solution containing 15.2 grams (0.0605 mole)2-mercapto-4-methyl-5-carbanilino thiazole, 300 ml. ethyl alcohol and3.8 grams (0.0605 mole) 90% potassium hydroxide. The procedure issimilar to the one described above. The product, melting point 214-216C., is obtained in a 69.9% yield. After recrystallization fromdimethylformamide, a sample of the product melts at 224- 226 C. Analysisof the 1-[(4-methyl-5-carbanilino)-2- thiazoly1thio1phthalazine shows14.10% nitrogen and 16.59% sulfur. Calculated percentages for C H N OSare 14.81% nitrogen and 16.95 sulfur.

The compound 1-(4-methyl-5-acety1-2-thiazolylthio)- phthalazine isprepared in a similar manner as described above except 17.3 grams (0.1mole) 2-mercapto-4-methyl- S-acetyl thiazole is used as a reactant inplace of 2-mercaptobenzothiazole. The product, melting point 199- 202C., is obtained in a 91.2% yield. After recrystallizaticn fromdimethylformamide, a sample of the product melts at 206207 C. Analysisof the 1-(4-methyl-5- acetyl-Z-thiazolylthio)phthalazine shows 13.54%nitrogen and 20.88% sulfur. Calculated percentages for 1-(4-methyl-5-acetyl-2-thiazolylthio) phthalazine are 13.94% nitrogen and21.28% sulfur.

The compound 1-(2-benzoxazo1ylthio)phthalazine is prepared in a similarmanner as described above except 15.1 grams (0.1 mole)2-mercaptobenzoxazole is used as a reactant in place of2-rnercaptobenzothiazole. The product, melting point 152-154 C., isobtained in a 68% yield. After recrystallization from ethyl alcohol, asample of the product melts at 162l63 C. Analysis of the 1-(Z-benzoxazolylthio)phthalazine shows 15.02% nitrogen and 10.60% sulfur.Calculated percentages for C H N OS are 15.05% nitrogen and 11.48%sulfur.

The compound 1-(2-benzimidazolylthio)phthalazine is prepared in asimilar manner as described above except 15.1 grams (0.1 mole)Z-mercaptobenzirnidazole is used as a reactant in place ofZ-mercaptobenzothiazole. The product, melting point 188190= C., isobtained in a 45.2% yield. After recrystallization from ethyl alcohol, asample of the product melts at 191 -192 C. Analysis of the1-(2-benzimidazo1ylthio)phthalazine shows 19.59% nitrogen and 11.57%sulfur. Calculated percentages for C H N S are 20.13% nitrogen and11.52% sulfur.

The compound 1-(4,6-climethyl 2 pyrimidinylthio)- phthalazine isprepared by adding in one portion 33 grams (0.2 mole) of l-chlorophthalazine to a stirred solution containing 35.4 grams (0.2 mole)4,6-dimethyl-2- pyrimidinethiol hydrochloride, 600 ml. ethyl alcohol and26.4 grams (0.4 mole) potassium hydroxide. The procedure is similar tothe one described above. The product, melting point 184-186 (3., isobtained in an 18.7% yield. After recrystallization from ethyl alcohol,a sample of the product melts at 189 190 C. Analysis of the1-(4,6-dirnethyl-Z-pyrimidinylthio)phthalazine shows 20.53% nitrogen and11.71% sulfur. Calculated percentages for C H N S are 20.88% nitrogenand 11.95% sulfur.

The preparation of 1-[(4-methyl-5-carboxy)-2-thiazo1y1thio1phthalazineis illustrated by the following reaction.

011.020 0 0 0 our. /\N

| l N s N or CHQC CIlCOOC2H slowly to the stirred filtrate until a pH of4 is obtained. The resulting solid is collected by filtration, washedwith water until neutral to litmus and air dried at 25 30 C. Theproduct, melting point 163 166 C., is obtained in a 75.6% yield. Afterrecrystallization from ethyl acetate, a sample of the product melts at174-175 C. Analysis of the 1-[(4-methyl-5-carboxy)-2-thiazolylthio]-phtl1alazine shows 13.36% nitrogenand 21.40% sulfur. Calculated percentages for C -H N O S are 13.85%nitrogen and 21.14% sulfur. The infrared spectrum confirms the structureof 1- (4-methyl-5-carboxy) -2-thiazolylthio] phthalazine.

The compound S (phthalazin 1-yl)-N,N-3-oxapentamethylenedithiocarbamateis prepared by adding slowly 7.6 grams (0.1 mole) of carbon disulfied toa stirred solution containing 8.7 grams (0.1 mole) of morpholine, 200ml. of ethyl alcohol, and 16 grams (0.1 mole) of 25% aqueous sodiumhydroxide. After stirring at 25 30 C. for one hour, 16.5 grams (0.1mole) of l-chlorophthalazine is added in one portion. The stirredreaction mixture is heated at 75 -80 C. for 24 hours. After cooling to25 C., 600 ml. of water is added and stirred at 010 C. for 15 minutes.The solid is collected by filtration, washed with water until neutral tolitmus and air dried at 25 30 C. The product, melting point 153-155 C.,is obtained in an 82.5% yield. After recrystallization fromdimethylformamide, the melting point of a sample of the product is183-184 C. Analysis of the S-(phthalazin-1 yl) N,N 3oxapentarnethylenedithiocarbamate shows 14.37% nitrogen and 22.03%sulfur. Calculated percentages for C H N OS are 14.42% nitrogen and22.00% sulfur.

The compound S (phthalazin 1-yl)N,N-diethyldithiocarbamate is preparedin a similar manner as the S- (phthalazin 1yl)-N,N-3-oxapentamethylenedithiocarbamate described above except 7.3grams (0.1 mole) of diethylamine is used in place of morpholine and thestirred reaction mixture is heated at 5060 C. for six hours. Aftercooling to 25 C., 300 ml. of water and 400ml. of ethyl ether are added.After stirring for 15 minutes, the separated ether layer is washed withwater until netural to litmus and dried over sodium sulfate. The etheris removed in vacuo at a maximum temperature of 30 C. at 12 mm. Hg. Theresulting solid is air dried at 25- 30 C. The product, melting point8590 C., is obtained in a 65% yield. After recrystallization from ethylalcohol, a sample of the product melts at 109110 C. Analysis of theS-(phthalazin-l-yl)N,N-diethyldithiocarbamate shows 15.10% nitrogen and23.93% sulfur. Calculated percentages for C H N S are 15.15% nitrogenand 23.12% sulfur.

The compound S-(phthalazin-1-yl)N,N-hexamethylenedithiocarbamate isprepared in a similar manner as S- (phthalazin 1yl)N,N-3-oxapentamethylenedithiocarbamate described above except 10grams (0.1 mole) hexamethylenimine is used as a reactant in place ofmorpholine. The product, melting point 140-143 C., is obtained in a 99%yield. After recrystallization from ethyl alcohol, a sample of theproduct melts at 153154 C. Analysis of the S (phthalazin1-yl)N,N-hexamethylene dithiocarbamate shows 13.37% nitrogen and 20.60%sulfur. Calculated percentages for C15H11N3S2 are 13.85% nitrogen and21.13% sulfur.

The compound S-(phthalazin-1-yl)N,N-dimethyldithiocarbamate is preparedin a similar manner as S-(phthalazin 1yl)N,N-3-oxapentamethylenedithiocarbamate described above except 18grams (0.1 mole) of 25% dimethylamine is used as a reactant in place ofmorpholine. The product, melting point 122127 C., is obtained in an 88%yield. After recrystallization from ethyl alcohol, a sample of theproduct melts at 150152 C. Analysis of the S-(phthalazin-l-yl)N,N-dimethyldithiocarbamate shows 16.34% nitrogen. Thecalculated percentage for C H N S is 16.85% nitrogen.

The compound S (phthalazin-l-yl)N,N-diisopropyldithiocarbamate isprepared in a similar manner as S- (phthalazin 1yl)N,N-3-0xapentamethylenedithiocarbamate described above except 10.1grams (0.1 mole) diisopropylamine is used as a reactant in place ofmorpholine. The product, melting point 140145 C., is obtained in a 39.2%yield. After recrystallization of a sample of the product from analcohol-acetone mixture, the melting point is 191-192 C. Analysis of theS-(phthalazin-l-yl) N,N-diisopropyldithiocarbamate shows 13.54%nitrogen. The calculated percentage for C H N S is 13.76% nitrogen.

The compound S-(1H-l,2,4-triazol-5,yl)N,N-dipropyldithiocarbamate isprepared by heating at 55 56 C. for 30 minutes a charge containing 40.4grams (0.4 mole) of 1,2,4-triazole-5-thiol, 800 ml. of acetone, and 25.2grams (0.4 mole) of potassium hydroxide. After cooling to 25 C., 71.6grams (0.4 mole) of dipropylthiocarbonyl chloride is added in oneportion. The stirred mixture is heated at 55 -56 C. for five hours andthen filtered hot to remove the potassium chloride. The filtrate isadded to 2000 grams of ice water and stirred at 010 C. for one hour. Theprecipitate is collected by filtration, washed with water until neutralto litmus, and air dried at 25- 30 C. The product, melting point 9095C., is obtained in a 65.5% yield. After recrystallization from ethylacetate, a sample of the product melts at 117119 C. Analysis of theS-(1H-1,2,4-triazol-5-yl)N,N-dipropyldithiocarbamate shows 22.45%nitrogen and 26.31% sulfur. Calculated percentages for C H N S are22.93% nitrogen and 26.24% sulfur.

The compound S (1H-1,2,4-triazol-5-yl)N,N-dibutyldithiocarbamate isprepared by adding 41.6 grams (0.2 mole) of dibutylthiocarbonyl chlorideto a stirred solu-' tion containing 20.2 grams (0.2 mole)1H-1,2,4-triazole- 5-thiol, 300 ml. acetone, 20 ml. of water, and 12.6grams (0.2 mole) 90% potassium hydroxide, and the mixture is stirred at25 -30 C. for 24 hours. After the addition of 300 ml. of water and 400ml. of ethyl ether, the reaction mixture is stirred at 25 30 C. for 15minutes. The separated ether layer is washed with water until thewashings are neutral to litmus and then dried over sodium sulfate. Theether is removed in vacuo at a maximum temperature of 80-90 C. at 1-2mm. Hg. The product, a black-colored liquid, is obtained in a 77% yield.Analysis of the S (1H 1,2,4-triazol-5-yl)N,N-dibutyldithiocarbamateshows 20.36% nitrogen. The calculated percentage for C H N S is 20.57%nitrogen.

The compound S-(1I-I-1,2,4-triazol 5 yl)-N,N-diethyldithiocarbamate isprepared in a similar manner as S (1H 1,2,4 triazol5-yl)N,N-dipropyldithiocarbamate described above except 60.4 grams (0.4mole) of diethylthiocarbonyl chloride is used in place ofdipropylthiocarbonyl chloride. The product, melting point 158- 161 C.,is obtained in a 52% yield. After recrystallization from ethyl alcohol,a sample of the product melts at 172- 173 C. Analysis of theS-(1H-1,2,4-triazol-5-yl)N,N-diethyldithiocarbamate shows 25.41%nitrogen. The calculated percentage for C'7H12N4S2 is 25.90% nitrogen.

The compounds S-(1H-1,2,4-triazol-5-yl)N-ethyldithiocarbanilate isprepared in a similar manner as S-(1H-1,2,- 4-triazol-5-yl)N,Ndipropyldithiocarbamate described above except 80 grams (0.4 mole)N-ethyl-N-phenyl thiocarbonyl chloride is used in place ofdipropylthiocarbonyl chloride. The product, melting point 148 C., isobtained in a 68.5% yield. After recrystallization from ethyl alcohol, asample of the product melts at 191 192 C. Analysis of theS-(1H-1,2,4-triazol-5-yl)-N-ethyl dithiocarbanilate shows 20.36%nitrogen. The calculated percentage for C H N S is 21.19% nitrogen. Theremaining compounds of this invention are prepared in a similar mannerto the preparations described, supra, with comparable results.

The following tables illustrate the useful properties of the compoundsof this invention as vulcanization accelerators in sulfur vulcanizablerubber. For the rubber stocks tested and described below, asillustrative of the utility, Mooney scorch times are determined by meansof Stock: CompoundContinued 101-[(4-methyl-5-carbamoyl)-2-thiaz01ylthio]- a Mooney plastometer. Thetime 1 represents the time In phthalazine. minutes required for theMooney reading to rise five 11 1-[ (4-methyl-5-carbaniuno-2-thiaz0lylth10] po1nts above the minimum viscosity of the rubber. The5 phthalazine. known accelerators, MBT, Santocure, and Santocure NS, 12MBT.

TABLE I Cure Time (Mins.)

at Stock 144 A-l Masterbatch 161 161 161 101 161 161 NeozoneD 1.0 1.01.0 1.0 1.0 1.0 Sulfur 2.5 2.5 2.5 2.5 2,5 2.5 Accelerator 0.5 v 62 O.69 0. 9 0.59 0.58 Mooney Scorch at 135 0., t 9. 7 8.8 8.7 9. 3 9.1 12.8Stress-Strain:

Modulus 300, p.s.i 3O 2, 650 2, 340 2, 050 2, 300 1, 470 1, 2 0 45 2,560 2, 340 2, 000 2, 340 1, 590 1. 270 60 2, 560 2, 280 2, 050 2,100 1.570 1, 460 Ultimate Tensile Strength, p.s.i 4, 050 3, 906 3, 900 4,0002, 500 2.080 45 4, 500 3, (340 3, 380 3, 750 2, 460 2, 430 60 4, 250 3,640 3, 490 3, 400 2, 430 2, 050 Ultimate Elongation,

percent 30 470 500 500 490 450 450 45 480 450 460 470 430 460 60 470 450460 450 430 400 Cure Time (Mins Stock A-1 Masterbatch... 161 161 161 161161 161 Neozone D....- 1.0 1.0 1.0 1.0 1.0 1.0 Sulfur 2. 5 2. 5 2. 5 2.5 2. 2. 5 Accelerator 0. 54 O. 64 0.63 0. 63 0.79 0. Mooney Scorch at135 0., t5 8. O 5. 3 9. 5 17. 5 l0. 3 5. O Stress-Strain:

Modulus 300, p.s.l 3O 2, 430 2, 450 2, 390 1, 440 2, 050 2, 050 2, 6002, 500 2, 430 1, 730 2. 200 2. 050 2, 360 2. 480 2, 430 1, 820 2, 200 2,Ultimate Tensile Strength, p.s.i 30 4,310 2, 220 3, 740 2, 340 3, 740 3,480

45 3, 940 3, 3, 900 2, 740 3, 320 H 60 4, 050 2, 450 3, 700 2, 460 3,280 3, 360 Ultimate Elongation,

percent 30 490 400 450 450 480 480 are included in the data forcomparison purposes. MBT designates Z-mercaptobenzothiazole, andSantocure NS is the trademark forN-tert-butyl-Z-benzothiazolesulfenamide. Santocure is the trademark forN-cycl0hexyl-2- benzothiazole sulfenamide. The antioxidant Neozone D isincluded in the stocks. The active ingredient for Neozone D is reportedto be N-phenyl-beta naphthylamine.

An A-l masterbatch as used in Table I is composed of:

Parts Natural rubber smoke sheets 100 High abrasion furnace black 5OStearic acid 3 Zinc oxide 5 Hydrocarbon softener 3 Total parts 161 Thenumerical stocks 2 through 11 in Table I represent rubber containing thecompounds of this invention. The stocks in Table I contain the followingcompounds.

Stock: Compound 1 Santocure.

2 1-(Z-benzothiazolylthio)phthalazine.

3 1-(6-ethoxy-2-benzothiazolylthio)phthalazine.

4 1-(S-chloro-Z-benzothiazolylthio)phthalazine.

5 1-(Z-benzoxazolylthio)phthalazine.

6 l-(Z-benzimidazolylthio)phthalazine.

7 1-(4-methyl-2-thiazolylthio)phthalazine.

8 1-[(4-methyl-5-carb0xy)-3-thiazolylthio] phthalazine.

9 l-(4-methyl-5-acetyl-2-thiazolylthio)- phthalazine.

Table II illustrates rubber cure properties of the compounds of thisinvention in an A-S masterbatch. An A-S masterbatch is composed of:

Parts Natural rubber smoke sheets 100 High abrasion furnace black 50Zinc oxide 3.0 Stearic acid 2.0 Hydrocarbon softener 3.0 Saturatedpolymerized petroleum hydrocarbon 3.0

The numerical stocks 3 through 7 in Table II represent rubber containingthe compounds of this invention. The stock numbers in Table 11 containthe following compounds.

Although dithiocarbamates are not generally delayed action accelerators,S-(phthalazin 1 yl)N,N-3-oxapentamethylenedithiocarbamate is anexception according 11) the Mooney scorch of 10.6 minutes reported inTable II.

TABLE II Cure Time Stock (mins.) at14 1 2 3 4 5 6 7 C. A-5 Masterbatch161 151 161 161 161 161 161 NeozoneD 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Sulfur2.5 2.5 2.5 2.5 2.5 2.5 2.5 Accelerator 0.5 0.5 0.5 0.5 0.5 0.5 0.5Mooney Scorch at 135 0., t 10.0 5.1 7. 4 7. 3 10. 6 4. 7 9. 6Stress-Strain:

Modulus 300,p.s.i 45 2, 680 2,200 2,170 2,170 1,750 2,230 1, s10 602,700 2,270 2, 040 1,950 1,690 2,220 1, 680 Ultimate Tensile Strength,p.s.i. 45 4,250 3, 510 3,460 3, 560 2, 770 3, 460 3, 040 60 4, 000 3,220 3,560 2, 470 2,590 3,500 2, 080 Ultimate Elongation, percent 45 4460 450 480 420 440 450 60 430 400 490 360 400 430 400 The compound1-(4,6-dirnethyl 2 pyrimidinylthio)- wherein Z is oxygen, NH or sulfurand A is orthophthalazine is an accelerator for the vulcanization ofphenylene, ch-loroorthophenylene, lower alkylrubber comparable to MBTbut much less scorchy than orthophenylene or lower alkoxyorthophenyl-MBT. The Mooney scorch reading at 135 C. fora naene; or tural rubberstock containing MB-T shows five minutes. The same stock without MBT butcontaining 1-(4,6-dimethyl-Z-pyrirnidinylthio)phthalazine shows 10.7minutes for 1 The remaining compounds of this invention are also usefulvulcanization accelerators in rubber.

It is intended to cover all changes and modifications of the examples ofthe invention herein chosen for purh i R" i lower lk l poses ofdisclosure which do not constitute departures from the spirit and scopeof the invention. 0

I claim: 1. The method of vulcanizing a sulfur-vulcanizable diene rubberwhich comprises:

mixing with the rubber a sulfur containing vulcanizing agent and anaccelerating amount of a compound of the formula wherein is1H-1,2,4-triazol-5-yl or phth'alazin-l-yl and wherein T is 4,6-di(loweralkyl)pyrimidin-2-yl;

carbon and not more than one member is nitrogen;

carbamoyl, carbanilino, carboxy or hydrogen and R is lower alkyl andheating the mixture at vulcanizing temperature.

2. The method of vulcanizing rubber as described in claim 1 wherein theaccelerating agent is 1-(2-benzothiazolylthio phthalazine.

3. The method of vulcanizing rubber as described in claim 1 wherein theaccelerating 'agent is S-(phthalazin-lyl)N,N-3-oxapentamethylenedithiocarb-amate.

4. The method of vulcanizing rubber as described in claim 1 wherein theaccelerating agent is 1-(4-methyl-5- acetyl-2-thiazolyt-hio)phthalazine.

5. The method of vulcanizing rubber as described in claim 1 wherein theaccelerating agent is S-(1H-1,2,4- triazol-S-yl)N,N-dipropyldithiocarbamate.

6. The method of vulcanizing rubber as described in claim 1 wherein theaccelerating agent is S-(1H-1,2,4- triazo-l-5-yl)N-ethyldithiocarbanilate.

References Cited UNITED STATES PATENTS 2,352,944 7/1944 DAlelio 260-3083,084,163 4/1963 Wilhnund 260-308 3,218,285 4/1965 Siiling 260-308JOSEPH L. SCHOFER, Primary Examiner.

D. K. DENENBERG, Assistant Examiner.

1. THE METHOD OF VULCANIZING A SULFUR-VULCANIZABLE DIENE RUBBER WHICHCOMPRISES: MIXING WITH THE RUBBER A SULFUR CONTAINING VULCANIZING AGENTAND AN ACCELERATING AMOUNT OF A COMPOUND OF THE FORMULA